Resolution agreements between the US Office of Civil Rights and the University of Cincinnati, Youngstown State University, and South Carolina Technical College System provide the most accepted definition:

“Accessible” means a person with a disability is afforded the opportunity to acquire the same information, engage in the same interactions, and enjoy the same services as a person without a disability in an equally effective and equally integrated manner, with substantially equivalent ease of use. The person with a disability must be able to obtain the information as fully, equally and independently as a person without a disability.

Accessibility is the degree to which a product, device, program, service, resource, or environment is available to a given user. If a building has a wheelchair ramp leading to its main entrance, that entrance is accessible to wheelchair users. If a lecture includes sign language interpreters, that lecture is accessible to attendees who are deaf or hard of hearing and who understand sign language.

What is digital accessibility?

Digital accessibility is when technology has been designed in a way so that it can be accessed by all users. This includes electronic documents, websites, software, hardware, video, audio, and other digital assets. People who interact with technology are extremely diverse. They have a wide variety of characteristics, and we cannot assume that they’re all using a traditional monitor for output, or keyboard and mouse for input. Consider these users:

• Most individuals who are blind use either audible output (products called screen readers that read web content using synthesized speech), or tactile output (a refreshable Braille device).
• Individuals with learning disabilities such as dyslexia may also use audible output. This is often referred to as Text-to-Speech (TTS).
• Individuals with low vision may use screen magnification software that allows them to zoom into a portion of the visual screen.
• Many others with less-than-perfect eyesight may enlarge the font on websites using standard browser functions, such as Ctrl + in Windows or Command + in Mac OS X.
• Individuals with fine motor impairments may be unable to use a mouse, and instead rely exclusively on keyboard commands, or use assistive technologies such as speech recognition, head pointers, mouth sticks, or eye-gaze tracking systems.
• Individuals who are deaf or hard of hearing are unable to access audio content, so video needs to be captioned and audio needs be transcribed.
• Individuals may be using mobile devices including phones, tablets, or other devices, which means they’re using a variety of screen sizes and a variety of gestures or other user interfaces for interacting with their devices and accessing content.

When technology is designed in an accessible fashion, it works for all of these users, and countless others not mentioned.

The World Wide Web Consortium (W3C) summarizes web accessibility nicely in their Web Content Accessibility Guidelines (WCAG). WCAG 2 is organized into the following four key concepts:

1. Perceivable - Information and user interface components must be presentable to users in ways they can perceive.
   • This means that users must be able to perceive the information being presented (it can't be invisible to all of their senses)
2. Operable - User interface components and navigation must be operable.
   • This means that users must be able to operate the interface (the interface cannot require interaction that a user cannot perform)
3. Understandable - Information and the operation of user interface must be understandable.
   • This means that users must be able to understand the information as well as the operation of the user interface (the content or operation cannot be beyond their understanding)
4. Robust - Content must be robust enough that it can be interpreted reliably by a wide variety of user agents, including assistive technologies.
   • This means that users must be able to access the content as technologies advance (as technologies and user agents evolve, the content should remain accessible)

Resources for this content:

• University of Washington: Accessible Technology
• Web Content Accessibility Guidelines 2.0 (WCAG)